Head and neck squamous cell carcinoma (HNSCC) is the sixth most common non-skin cancer in the world, with an incidence of ˜600,000 cases per year and mortality rate of ˜50%. The major risk factors for HNSCC are tobacco use, alcohol consumption, and infection with human papilloma virus (HPV). Despite advances in knowledge of its epidemiology and pathogenesis, the survival rates for many types of HNSCC have improved little over the past forty years. The overall 5-year survival rate of HNSCC patients is only about 50%, and this number has not changed in more than three decades.
Tobacco, alcohol consumption and viral agents are the major risk factors for development of HNSCC. These risk factors, together with genetic susceptibility, result in the accumulation of multiple genetic and epigenetic alterations in a multistep process of cancer development (Kim and Califano, Int J Cancer 112:545-53, 2004). However, the underlying cellular and molecular mechanisms that contribute to the initiation and progression from normal epithelia to invasive squamous cell carcinoma have not been clearly delineated (Mao et al., Cancer Cell 5:311-6, 2004). A better understanding of molecular carcinogenesis of HNSCC would be valuable in its early detection, prognostication and development of new strategies for prevention and treatment.
As such, a deeper understanding of HNSCC pathogenesis is needed to promote the development of improved therapeutic approaches. There is still a need for methods of treating HNSCC more effectively.